Multiple screw c clamp



y 1948- H. J. FRANK 2,440,820

MULTIPLE SCREW G CLAMP Filed March 18, 1944" firfierffrania Patented May4, 1948 orrrce This invention relates to clamps and has relation moreparticularly to a device of this kind of a C typ and it is an object ofthe invention to provide a clamp of this kind constructed in a manner tomake the same particularly advantageous for use in holding the workagainst a seesaw type base.

It is also an object of the invention to provide a clamp of this kindincluding a plurality of pressure screws .coacting with a clamping baseof aseesaw or rocker type.

In the use of the ordinary type C clamp employing a single pressurescrew, there is a tendency for the clamp to walk or creep when tightenedand it often occurs that by the use of only a single clamping point, theclamp is of reduced efliciency. It is a further object of the inventionto provide a clamp constructed in a manner to obviate thesedisadvantages and which is particularly effective when used to hold twopieces of metal together while doing any machining or hand work uponsuch metal pieces.

The invention consists in the details of construction and in thecombination and arrangement of the several parts of my improved clampwhereby certain important advantages are attained, as will behereinafter more fully set forth.

In order that my invention may be better understood, I will now proceedto describe the same with reference to the accompanying drawings,wherein:

Figure 1 is a view in side elevation of a clamp constructed inaccordance with an embodiment of my invention, with a portion brokenaway;

Figure 2 is a view in front elevation of the device as herein comprised;and

Figure 3 is a view in top plan.

In the embodiment of the invention as illustrated in the accompanyingdrawings, the improved clamp comprises a body I of a ctype and which isreinforced from substantially one end to the other by an outstandingstrengthening rib 2. This rib 2 at one extremity of the body I istransversely thickened or enlarged to provide a head 3 through whichthreads the elongated clamping screws 4.

These screws 4 are in parallelism and are spaced apart in a directionlengthwise of the head 3. These screws 4 are also in relatively closeproximity one to the other and the inner end portions of these screws 4each has in swlveled connection therewith, as at 5, a foot 6 forclamping or holding contact with the work.

The feet 6 carried by the screws 4 coact with the base or jaw 1 of aseesaw or rocker type. This 2 base or jaw I is elongated and is providedalong its side margins with the perpendicularly related flanges 8 whichoverlie the side faces of the end portion of the body I or an extendedextremity 9 of the flange 2,

These flanges 8 are pivotally held to said. body or flange extension 9by a pivot member In, herein disclosed as a conventional type of rivet.The pivotal mounting H] for the base or jaw I is at a pointsubstantially midway of the ends of said base or jaw 1 or midway betweenthe screws 4.

The outer end portions of the screws 4 are provided with theenlargements or heads ll having disposed therethrough the openings ['2whereby a suitable cross-bar or other member may be readily employed toefiect the desired rotation of the screws 4.

My improved clamp is particularly adapted for,

use to hold two pieces of metal together while doing any machining orhand work upon such pieces although, of course, I do not wish to beunderstood as limiting myself to such specific use. It is believed to beobvious that with the use of my clamp, the coaction between the screws 4and the base or jaw I is such as to assure an equal clamping pressureupon tightening of either of the screws 4, and it is furthermorebelieved to be readily apparent that with the use of my improved clamp,the tendency of the work with which it is engaged to, walk or creep iseliminated.

It is also of advantage to provide the outer or working face of the baseor jaw l at the transverse center thereof with a groove 14 extendingentirely along said base or jaw. This groove l4 makes it convenient touse the clamp to grip a piece of round rod or stock against a surface.

From the foregoing description it is thought to be obvious that a clampconstructed in accordance with my invention is particularly well lyingin a common plane and being directed toward the opposite end portion,and a base with which the screws coact, mounted upon the said oppositeend' portion of the body for rocking movement on an axis perpendicularto the surface of said common plane, the said axis lying in a planepassing centrally between the screws.

2. A clamp comprising a C-shaped body. spaced parallel screws threadedthrough one end portion of the body, the longitudinal axes of saidscrews lying in a common plane and being directed toward the oppositeend portion, a base with which the screws coact, mounted upon the saidopposite end portion of the body for rocking movement on an axisperpendicular to the surface of said common plane, the said axis lyingin a plane passing centrally between the screws, said base having a fiattop surface having a length extending in the direction in which thescrews are spaced, and a channel formed in and longitudinally of saidtop surface, its longitudinal axis lying in said common 4 nmnnncns orrnnThe following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 242,959 Naglee June 14, 1881359,815 Sargent Mar. 22, 1887 431,641 Beach July 8, 1890 1,063,332 DiehlJune 3, 1913 1,203,152 Steudner Oct. 31,1916

Vidinghofi Aug. 7, 1923

